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<head><meta charset="utf-8"><title>rmeta consistency · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html">rmeta consistency</a></h3>

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<a name="206105766"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206105766" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206105766">(Aug 06 2020 at 05:17)</a>:</h4>
<p>hi, I'm working on build reproducibility and building a crate on different machines but with otherwise identical dependency trees, source code, etc. the rmeta files from the two crates differ in that all the item addresses in the file seem to be off by 2. how do i figure out what the source of the inconsistency is? having read through librustc_metadata i haven't figured out an easy way to do that.</p>



<a name="206118408"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206118408" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206118408">(Aug 06 2020 at 09:04)</a>:</h4>
<p>Can you post a link to the repository?</p>



<a name="206166179"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166179" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166179">(Aug 06 2020 at 16:44)</a>:</h4>
<p>sadly i can't, it's a private repo (that isn't owned by me). are there any resources that will let me inspect the contents of an rmeta file without reverse-engineering the stuff in librustc_metadata?</p>



<a name="206166459"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166459" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166459">(Aug 06 2020 at 16:47)</a>:</h4>
<p><span class="user-mention" data-user-id="328006">@Jude Taylor</span> Your best bet would be to modify this function in a local build of rustc: <a href="https://github.com/rust-lang/rust/blob/c15bae53b5c40db2682211836f892a5a44065e10/src/librustc_metadata/rmeta/decoder.rs#L585-L593">https://github.com/rust-lang/rust/blob/c15bae53b5c40db2682211836f892a5a44065e10/src/librustc_metadata/rmeta/decoder.rs#L585-L593</a></p>



<a name="206166489"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166489" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166489">(Aug 06 2020 at 16:47)</a>:</h4>
<p>and print out additional information</p>



<a name="206166529"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166529" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166529">(Aug 06 2020 at 16:47)</a>:</h4>
<p>you can then use <code>rustc -Z ls /path/to/your_file.rmeta</code></p>



<a name="206166560"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166560" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166560">(Aug 06 2020 at 16:48)</a>:</h4>
<p>oh, i didn't know about the ls option!</p>



<a name="206166636"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166636" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166636">(Aug 06 2020 at 16:48)</a>:</h4>
<p>it currently just prints dependencies</p>



<a name="206166672"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166672" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166672">(Aug 06 2020 at 16:48)</a>:</h4>
<p>it gives me "entered unreachable code" when i try to run it in the shell</p>



<a name="206166691"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166691" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166691">(Aug 06 2020 at 16:48)</a>:</h4>
<p>without building a new rustc or anything, just with <code>rustc -Z ls lib1.rmeta</code></p>



<a name="206166706"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166706" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166706">(Aug 06 2020 at 16:48)</a>:</h4>
<p>hmm</p>



<a name="206166722"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166722" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166722">(Aug 06 2020 at 16:49)</a>:</h4>
<p>are you sure you're using the same rustc that you built the rmeta with?</p>



<a name="206166746"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166746" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166746">(Aug 06 2020 at 16:49)</a>:</h4>
<p>the rmeta format changes frequently</p>



<a name="206166758"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166758" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166758">(Aug 06 2020 at 16:49)</a>:</h4>
<p>oh, no, i'm not sure</p>



<a name="206166767"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166767" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166767">(Aug 06 2020 at 16:49)</a>:</h4>
<p>but i built the rmeta file with a stable compiler</p>



<a name="206166795"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166795" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166795">(Aug 06 2020 at 16:49)</a>:</h4>
<p>that won't work, then</p>



<a name="206166799"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166799" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166799">(Aug 06 2020 at 16:49)</a>:</h4>
<p>so i used rustup to get the closest nightly release to 1.43.0 stable that i could</p>



<a name="206166887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166887">(Aug 06 2020 at 16:50)</a>:</h4>
<p>but if i build it locally it will either work or i can just goto the site of the panic directly and figure out why it's happening</p>



<a name="206166890"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166890" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166890">(Aug 06 2020 at 16:50)</a>:</h4>
<p>I would recommend matching the rustc versions exactly</p>



<a name="206166894"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166894" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166894">(Aug 06 2020 at 16:50)</a>:</h4>
<p>which is at the very least a lead</p>



<a name="206166918"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166918" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166918">(Aug 06 2020 at 16:50)</a>:</h4>
<p>you can do RUSTC_BOOTSTRAP=1 on the stable compiler to get the -Z flag to work</p>



<a name="206166924"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166924" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166924">(Aug 06 2020 at 16:50)</a>:</h4>
<p>oh</p>



<a name="206166946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166946">(Aug 06 2020 at 16:50)</a>:</h4>
<p>(obviously, don't do this in prod, all stability bets are off with this flag)</p>



<a name="206166983"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206166983" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206166983">(Aug 06 2020 at 16:51)</a>:</h4>
<p>cool</p>



<a name="206167006"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167006" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167006">(Aug 06 2020 at 16:51)</a>:</h4>
<p>okay well to get more debug output i have to build rustc on my own anyway, so it doesn't matter</p>



<a name="206167024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167024">(Aug 06 2020 at 16:51)</a>:</h4>
<p>but that did work</p>



<a name="206167028"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167028" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167028">(Aug 06 2020 at 16:51)</a>:</h4>
<p>thanks</p>



<a name="206167058"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167058" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167058">(Aug 06 2020 at 16:51)</a>:</h4>
<p>What did you mean when you said "the addresses seem to be off by 2"?</p>



<a name="206167120"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167120" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167120">(Aug 06 2020 at 16:52)</a>:</h4>
<p>how were you inspecting the rmeta file?</p>



<a name="206167122"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167122" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167122">(Aug 06 2020 at 16:52)</a>:</h4>
<p>so i read the start of librustc_metadata/decoder or <a href="http://mod.rs">mod.rs</a> whichever one has the documentation in it</p>



<a name="206167131"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167131" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167131">(Aug 06 2020 at 16:52)</a>:</h4>
<p>and it says</p>



<a name="206167176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167176">(Aug 06 2020 at 16:52)</a>:</h4>
<p><code>Metadata header [...] is followed by the position of the CrateRoot, which is encoded as a 32-bit big-endian unsigned integer.</code></p>



<a name="206167198"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167198" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167198">(Aug 06 2020 at 16:53)</a>:</h4>
<p>and when looking at a hexdump of the two files, the position of the CrateRoot differs by 2</p>



<a name="206167264"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167264" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167264">(Aug 06 2020 at 16:53)</a>:</h4>
<p>i can actually see in hexdump where the inconsistency between the two files starts, but it's in the middle of a ton of binary data that i do not recognize whatsoever so it's not very helpful</p>



<a name="206167398"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167398" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167398">(Aug 06 2020 at 16:54)</a>:</h4>
<p>more specifically, CrateRoot in lib1.rmeta starts at <code>0x000a54e0</code> and in lib2.rmeta starts at <code>0x000a54e2</code></p>



<a name="206167454"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167454" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167454">(Aug 06 2020 at 16:55)</a>:</h4>
<p>are you building a library or a binary?</p>



<a name="206167468"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167468" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167468">(Aug 06 2020 at 16:55)</a>:</h4>
<p>lib</p>



<a name="206167491"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167491" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167491">(Aug 06 2020 at 16:55)</a>:</h4>
<p>if you notice any differences in the final object, that could give you a starting place</p>



<a name="206167523"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167523" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167523">(Aug 06 2020 at 16:55)</a>:</h4>
<p>yeah i guess it could</p>



<a name="206167569"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167569" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> bjorn3 <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167569">(Aug 06 2020 at 16:55)</a>:</h4>
<p>Is there any difference between the binary data before the <code>CrateRoot</code> except for one being 2 bytes longer?</p>



<a name="206167627"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167627" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167627">(Aug 06 2020 at 16:56)</a>:</h4>
<p>yeah, quite a lot</p>



<a name="206167642"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167642" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167642">(Aug 06 2020 at 16:56)</a>:</h4>
<p>i can put up a gist with a snippet of the hexdumps actually</p>



<a name="206167674"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167674" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Hill <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167674">(Aug 06 2020 at 16:56)</a>:</h4>
<p>Is there any chance you could get permission to share the repository, or try to minimize it to something that you could share?</p>



<a name="206167703"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167703" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167703">(Aug 06 2020 at 16:56)</a>:</h4>
<p>i know that would make it easier :P but this code is very very deep in a large dependency tree</p>



<a name="206167710"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206167710" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206167710">(Aug 06 2020 at 16:56)</a>:</h4>
<p>i'll see what i can do</p>



<a name="206208299"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206208299" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206208299">(Aug 06 2020 at 23:08)</a>:</h4>
<p>so, I identified the problem. it turns out that the textual output of every proc-macro invocation is added to the hash of a crate</p>



<a name="206208317"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206208317" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206208317">(Aug 06 2020 at 23:09)</a>:</h4>
<p>and the crate uses the <code>askama</code> crate which is some kind of html template code generator thing</p>



<a name="206208332"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206208332" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206208332">(Aug 06 2020 at 23:09)</a>:</h4>
<p>and it uses <code>include_bytes!(path/to/file)</code> to make up for proc-macros not being able to mark dependent files</p>



<a name="206208346"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rmeta%20consistency/near/206208346" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jude Taylor <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rmeta.20consistency.html#206208346">(Aug 06 2020 at 23:09)</a>:</h4>
<p>and that file path is different between the two different builds</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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